The field of this invention is the effecting of mass transfer between two immiscible fluids.
U.S. Pat. Nos. 3,754,337 and 3,758,404 are directed to methods of effecting mass transfer between two immiscible fluids. U.S. Pat. No. 3,758,404 discloses a method for effecting mass transfer between immiscible, concurrently flowing liquid-liquid phases including a conduit having a bundle of elongated fibers positioned therein. The fiber bundle is positioned within the conduit at a perforated node that also acts as the point of introduction for the first liquid which is deposited onto the fiber within the fiber bundle as a film. A second liquid is directed into the conduit and over the first liquid deposited on the fibers. The large area of contact between the first and second liquids provides for an efficient mass transfer therebetween. The first liquid deposited upon the fibers is moved along the fibers by the viscous drag occurring between the two concurrently flowing fluids. The first liquid in film form, sometimes referred to as the constrained phase, is moved along the fibers and eventually deposited in a collection vessel. The downstream end of the fiber bundle extends outwardly of the conduit into the collection vessel for the purpose of making direct fluid contact with fluid collected off of the bundle in order to prevent dispersion between the two phases. In this manner, mass transfer is efficiently effected between the two immiscible liquids without dispersion of one liquid into the other. U.S. Pat. No. 3,747,377 provides for a gas-liquid mass transfer process which is similar to the liquid-liquid mass transfer process just described. These processes have proved to be remarkable inventions providing mass transfer at high efficiency levels without dispersion of one fluid into the other.
Significant problems have arisen in the initial practice of the invention set forth in these patents. For example, it has been discovered that the viscous drag occurring between the concurrently flowing first and second fluids exerts stress upon the individual fibers within the fiber bundle which can cause the fibers to break, particularly with certain fiber materials, such as stainless steel wool. The problem is compounded due to the length of the fibers and the fact that these stresses tend to increase with the length of the fibers.